In the course of growing scarcity and increasing prices of energy, efforts are also increasingly undertaken to exploit water courses with low heights of fall and/or volume flows. Constructions are also applied in this process which are characterized by an especially simple configuration.
A hydroelectric power plant is known from U.S. Pat. No. 4,755,690 B1, comprising a dam which extends transversely to the direction of flow. Numerous power units are provided which respectively comprise a machine set with a turbine and a generator which have a common shaft. The individual machine sets are arranged in lines adjacent to one another and on top of one another and can be lowered to their working position by means of lifting devices. Only simple and sturdy constructions of the aforementioned machine sets can be considered in courses of rivers with low quantities of water and low flow velocities or low heights of fall. Seasonal differences in water quantities need to be taken into account in such courses of river as the differences between high water and low water can be very large. Rocks, driftwood or other bodies may be entrained during rushing flow as well as at low water. Such materials may cause damage to the machine set and blockage of the flow conduit of the turbine.
The invention is based on the object of providing a hydroelectric power plant which In one aspect, a miniature hydroelectric power plant of sturdy and simple configuration is provided that is especially suitable for the aforementioned conditions.
In another aspect, a turbine of the power plant includes a plurality of turbine blades which are arranged in the manner of marine screw propellers. A blade wheel includes a ring which encloses the rotational axis of the blade wheel and which carries the turbine blades on its inner circumference. The blade wheel is free from a shall or hub such that the blades are only fixed to the aforementioned ring. They protrude generally radially from the ring towards the rotational axis of the blade wheel. They are not fixed in any manner at their free ends. Instead, a passage remains between the free ends of the turbine blades through which any floating debris such as rocks, driftwood and the like is allowed to pass.
The stator of the generator encloses the ring and may be used by the same as a supporting bearing.
The power unit consisting of turbine and generator may be used in a river power plant, but also at locations where a flow occurs such as the coastal regions of bodies of water such as oceans.
The power plant may be used in a dam which is installed in the course of a river as a flow obstruction and is generally used for river training in order to decrease high flow velocities for example.